KR100479854B1 - Epoxy molding compound having improved heat-release property for use as semiconductor encapsulant - Google Patents

Abstract

The present invention relates to an epoxy resin composition for sealing semiconductor devices excellent in heat dissipation characteristics and corrosion resistance in a high temperature and high humidity environment, and more specifically, (1) epoxy resin, (2) curing agent, (3) curing accelerator, (4) The present invention relates to an epoxy resin composition for sealing a semiconductor device comprising natural crystalline silica and (5) a boron-based compound, and according to the present invention, an epoxy resin composition useful for package molding of a semiconductor device having high heat release can be provided.

Description

Epoxy resin composition for sealing semiconductor element with improved heat dissipation {EPOXY MOLDING COMPOUND HAVING IMPROVED HEAT-RELEASE PROPERTY FOR USE AS SEMICONDUCTOR ENCAPSULANT}

The present invention relates to an epoxy resin composition for sealing semiconductor devices having excellent heat dissipation characteristics and corrosion resistance under high temperature and high humidity environments, and more particularly, by applying natural crystalline silica and boron compounds, heat dissipation characteristics, corrosion resistance and moldability At the same time, the present invention relates to a high heat dissipation epoxy resin composition.

In recent years, the degree of integration of semiconductor devices is improving day by day, and thus, the size of wiring and the size of devices are rapidly progressing. On the other hand, packages that protect semiconductor devices from the external environment are becoming smaller and thinner, and demands for measures to prevent corrosion of chips and aluminum pads due to high heat release during operation and moisture penetration from the outside are accelerating. .

As described above, in a resin-sealed semiconductor device in which a large semiconductor device is sealed in a small and thin package, the frequency of failure such as package crack or corrosion of an aluminum pad may increase due to thermal stress caused by temperature and humidity changes in the external environment. . Therefore, as a solution for this, high reliability of the epoxy resin molding material for sealing has emerged strongly, and in order to lower stress in detail, a method of lowering the elastic modulus and a method of lowering the coefficient of thermal expansion have been introduced. To prevent this, use a high-purity component or apply an ion trapper to reduce the impurity content, a high-filling inorganic filler to reduce the moisture absorption, and a low viscosity epoxy resin and other additives. The method of increasing the adhesion between the chip or lead frame and the encapsulant has been introduced.

For example, as a method of lowering the elastic modulus, modification by various rubber components (see Japanese Patent Application Laid-Open Nos. 63-1894 and 5-291436) is studied, and a silicone polymer having excellent thermal stability is blended and modified. Epoxy resin molding materials are widely adopted. In this method, the silicone oil is incompatible with the epoxy resin, which is the base resin of the molding material, and a curing agent, and thus fine particles are dispersed in the base resin, thereby achieving a low modulus while maintaining heat resistance. On the other hand, for low thermal expansion, the method of increasing the filling amount of the inorganic filler having a low coefficient of thermal expansion is best, but the low flowability and high elasticity of the epoxy resin molding material due to the increase of the filling amount of the inorganic filler is a problem. In Korean Patent Publication No. 64-11355, a technique for incorporating a large amount of spherical fillers through the control of particle size distribution and particle size has been introduced.

However, it is possible to satisfy some of the requirements for modulus of elasticity by blending silicone polymers or increasing the filling amount of inorganic fillers, but it is difficult to secure moldability to a variety of package types, which remains a problem to be solved. have. In particular, for packages requiring high heat dissipation, alumina hydroxide is generally recommended as an inorganic filler. However, an encapsulant containing alumina hydroxide is vulnerable to moisture absorption. It is also known to be less filling than. On the other hand, when fused silica is applied, there is a limit in improving heat dissipation characteristics. On the other hand, when natural silica is applied, heat dissipation is superior to fused silica, but the filling and moldability are deteriorated due to the particle shape of silica. . If the excellent moldability of the material for semiconductor element sealing is not secured, defects such as inferiority and internal voids may occur during package molding, and as a result, it becomes vulnerable to external moisture, thereby increasing the possibility of corrosion of the semiconductor element, and resulting from thermal stress Fatal defects occur such as cracks.

The present invention is to solve the problems of the prior art as described above, as a resin composition for packaging a semiconductor device with high heat generation, by applying more than 80% by weight of natural crystalline silica and boron-based compound to ensure excellent moldability and corrosion resistance In addition, an object of the present invention is to provide an epoxy resin composition with remarkably improved heat dissipation characteristics.

That is, the present invention provides an epoxy resin composition for sealing a semiconductor device comprising the following components:

(1) epoxy resins;

(2) curing agents;

(3) curing accelerators;

(4) natural crystalline silica; And

(5) Boron compound.

In preparing the epoxy resin composition for semiconductor element sealing, the present inventors filled 80% by weight or more of natural crystalline silica having excellent thermal conductivity as an inorganic filler with respect to the entire resin composition to improve heat dissipation, and molding by adding a specific boron-based compound. In addition to improving the properties, it was possible to control the ionic impurities in the composition to prevent corrosion of chips and pads.

Hereinafter, the present invention will be described in more detail.

The epoxy resin of component (1) used in the present invention may be appropriately selected depending on the use in view of viscosity and structure, but it is preferable to use a low viscosity epoxy resin in view of moldability. For example, an orthocresol novolak resin having an epoxy equivalent of 170 to 270 or a biphenyl epoxy resin may be used alone or in combination, and the amount of use is preferably 3.5 to 10% by weight based on the total composition. .

As the curing agent of component (2) used in the present invention, a conventional phenol novolac resin, cresol novolac resin, Xylok resin, dicyclopentadiene resin having two or more hydroxyl groups and a hydroxyl equivalent of 100 to 200 Etc. may be used and one of these may be used alone, or two or more thereof may be used in combination. However, from the viewpoint of price and moldability, it is preferable to use at least 50% by weight of the phenol novolak resin as a whole of the curing agent component. In consideration of the composition ratio with the epoxy resin, the amount of the curing agent is preferably adjusted so that the epoxy equivalent to the hydroxyl equivalent falls within the range of 0.8 to 1.2, and the content in the total composition is preferably 2.0 to 10.0% by weight.

The curing accelerator of component (3) used in the present invention is a component necessary for promoting the curing reaction of the component (1) and the component (2), for example benzyldimethylamine, triethanolamine, triethylenediamine, dimethylamino Tertiary amines such as ethanol and tri (dimethylaminomethyl) phenol, imidazoles such as 2-methylimidazole and 2-phenylimidazole, and organic such as triphenylphosphine, diphenylphosphine and phenylphosphine Tetraphenylboron salts such as phosphine, tetraphenylphosphonium tetraphenylborate, and triphenylphosphine tetraphenylborate, and the like, and may be used alone or in combination of two or more thereof. It is preferable that it is 0.1 to 0.3 weight% with respect to a composition.

In the present invention, a high purity natural crystalline silica (component 4) having an average particle size of 2.0 to 35.0 µm is used as the inorganic filler, and the filling amount thereof is 80% by weight or more based on the whole composition. When the amount of natural silica is less than 80% by weight or when molten silica is applied instead of natural silica, the heat dissipation characteristics are deteriorated. In particular, when the amount is insufficient, sufficient strength and low thermal expansion are not realized, and moisture penetration is not achieved. It becomes easy and becomes fatal to aluminum pad corrosion. On the other hand, the upper limit of the filling amount of the inorganic filler should be selected in consideration of the moldability, it is preferable to use the 85% by weight or less.

As the boron-based compound of component (5) used in the present invention, 2ZnO.3B ₂ O ₃ .3.5H ₂ O (Compound 1) or 2ZnO.3B ₂ O ₃ (Compound 2) may be used alone or both. It is possible to use together. In the present invention, the boron-based compound serves as a moldability improving agent. In the epoxy resin composition for semiconductor element sealing, in order to impart flame retardancy, it is common to add a bromo epoxy flame retardant and an antimony flame retardant aid. However, since the antimony compound is generally high in density, there is a risk that the dispersion state becomes unstable when a large amount is applied to the resin composition, thereby causing a fatal molding failure. In the present invention, by adding the boron-based compound, it is possible to secure the same flame retardancy while reducing the amount of the antimony flame retardant aid, resulting in excellent dispersion stability and formability. Furthermore, since the boron-based compound acts as an ion trapping agent, there is an effect of removing the ion impurities in the composition, it is also possible to prevent the corrosion of the chip and the pad. The average particle size of the boron-based compound is 2 ~ 10 micrometers is suitable, the particle size is less than 2 micrometers dispersibility is reduced, and when it exceeds 10 micrometers, the specific surface area is reduced, the activity of the chip and the aluminum pad Corrosion may occur and flame retardancy may also decrease. It is preferable that the content of the boron-based compound in the resin composition of the present invention is 0.5 to 4.0% by weight, and when used at less than 0.5% by weight, the desired formability improvement and ion trapping effect cannot be obtained and exceed 4.0% by weight. When used, there is a disadvantage that the heat emission characteristics are poor.

In addition to the essential components of (1) to (5) described above, a bromo epoxy flame retardant may be used in the resin composition of the present invention, and in the case of using a flame retardant aid such as antimony trioxide and antimony pentoxide, the amount of the boron It is adjusted according to the amount of the compound used and is used up to 1.5% by weight based on the entire composition. If the content of the antimony flame retardant aid exceeds 1.5% by weight, a decrease in dispersibility and thus moldability may be caused.

The resin composition of the present invention may be a release agent such as a higher fatty acid, a higher fatty acid metal salt or an ester wax, a coloring agent such as carbon black or an organic or inorganic dye, a coupling agent such as an epoxy silane, an amino silane or an alkyl silane as necessary. Can be added.

The resin composition of the present invention is uniformly sufficiently mixed each component in a predetermined compounding amount using a Henssel mixer or Loedige mixer, and then melt kneaded with a roll mill or kneader. It can then be prepared according to the general method of cooling and grinding to obtain a final powder product.

As a method of sealing a semiconductor device using the epoxy resin composition produced in the present invention, transfer molding is the most commonly used method, or injection molding or casting. It is moldable.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Examples 1-3 and Comparative Examples 1-3

After weighing each component as shown in Table 1 and Table 2 below, the mixture was uniformly mixed using a Henschel mixer to prepare a powdery primary composition, followed by melting at 100 ° C. for 7 minutes using a mixing 2-roll mill. After kneading, the final epoxy resin composition was prepared by cooling and grinding.

The spiral flow was measured for the epoxy resin composition thus obtained, and after the specimen was prepared and post-cured at 175 ° C. for 6 hours, flexural strength, elastic modulus, thermal conductivity, and flame retardancy were measured. In addition, by molding the TO-220FP package (full package) to confirm the moldability, after curing after 168 hours, 200 hours, 300 hours, 500 hours and then absorbed under constant temperature and humidity conditions of 85 ℃ / 85% RH, respectively After 1 day at 25 ° C./50%RH, the chip and pads were observed for corrosion after the characteristic experiments using DC parameters. The results are summarized in Table 1 and Table 2 below.

(Unit: weight%) Composition Example 1 Example 2 Example 3 Epoxy resin Orthocresol novolac resin 5.5 8.5 6.0 Phenolic Novolak Resin 4.3 5.1 4.7 Triphenylphosphine 0.2 0.3 0.2 Natural Crystalline Silica 84 80 82 Boron Compound (1) 2.0 1.0 4.0 Boron-Based Compounds (2006.01) 1.0 2.0 0 Antimony trioxide 0.1 0.2 0.2 Bromine epoxy flame retardant 1.0 1.0 1.0 γ-glycithoxypropyltrimethoxysilane 0.4 0.4 0.4 Epoxy Modified Silicone Oil 1.0 1.0 1.0 Carbon black 0.2 0.2 0.2 Carnauba Wax 0.3 0.3 0.3 Spiral Flow (inch) 21 23 22 Flexural Strength (㎏ / ㎠) 15.1 15.0 14.2 Flexural modulus (㎏ / ㎠) 2200 2000 2100 Thermal Conductivity (cal / cm · sec · ℃ * 10 ^-3 ) 60 40 55 Moldability defects (void / death) 0/20 0/20 0/20 Flame retardant (1/8 inch UL) V-0 V-0 V-0 Chip corrosion 168 hours 0/5 0/5 0/5 200 hours 0/5 0/5 0/5 300 hours 0/5 0/5 0/5 500 hours 0/5 0/5 0/5 Pad corrosion 168 hours 0/5 0/5 0/5 200 hours 0/5 0/5 0/5 300 hours 0/5 0/5 0/5 500 hours 0/5 1/5 1/5

(Unit: weight%) Composition Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy resin Orthocresol novolac resin 5.8 8.9 7.3 Phenolic Novolak Resin 4.6 5.4 5.6 Triphenylphosphine 0.2 0.3 0.2 Natural Crystalline Silica 0 80 40 Fused silica 84 0 42 Boron Compound (1) 0 0 1.0 Boron-Based Compounds (2006.01) 0 0 1.0 Antimony trioxide 2.5 2.5 0 Bromine epoxy flame retardant 1.0 1.0 1.0 γ-glycithoxypropyltrimethoxysilane 0.4 0.4 0.4 Epoxy Modified Silicone Oil 1.0 1.0 1.0 Carbon black 0.2 0.2 0.2 Carnauba Wax 0.3 0.3 0.3 Spiral Flow (inch) 23 23 22 Flexural Strength (㎏ / ㎠) 14.3 14.5 14.2 Flexural modulus (㎏ / ㎠) 1900 2000 2005 Thermal Conductivity (cal / cm · sec · ℃ * 10 ^-3 ) 50 38 51 Moldability defects (void / death) 6/20 2/20 1/20 Flame retardant (1/8 inch UL) V-0 V-0 V-1 Chip corrosion 168 hours 0/5 0/5 0/5 200 hours 0/5 0/5 0/5 300 hours 0/5 0/5 0/5 500 hours 0/5 1/5 0/5 Pad corrosion 168 hours 0/5 0/5 0/5 200 hours 0/5 0/5 0/5 300 hours 1/5 2/5 0/5 500 hours 3/5 3/5 1/5

Through the comparison of Table 1 and Table 2, it can be seen that the epoxy resin composition according to the embodiment is better in terms of heat dissipation characteristics, moldability and corrosion resistance of the chip and pad compared to the comparative example.

As described in detail above, the present invention can provide an epoxy resin composition that is particularly useful for package molding of semiconductor devices with high heat generation.

Claims (3)

Epoxy resin composition for sealing a semiconductor device comprising the following components: (1) epoxy resins; (2) curing agents; (3) curing accelerators; (4) natural crystalline silica; And (5) Boron compound. The method of claim 1, 3.5 to 10 wt% of the epoxy resin; 2.0 to 10 wt% of the curing agent; 0.1 to 0.3% by weight of the curing accelerator; 80-85 wt% of the natural crystalline silica; And 0.5-4.0 wt% of the boron-based compound Epoxy resin composition for sealing a semiconductor device, characterized in that included. The epoxy resin composition for sealing a semiconductor device according to claim 1 or 2, wherein the boron compound is 2ZnO.3B ₂ O ₃ .3.5H ₂ O and / or 2ZnO.3B ₂ O ₃ .